GRD Journals- Global Research and Development Journal for Engineering | Volume 1 | Issue 7 | June 2016 ISSN: 2455-5703
Experimental Analysis of Heat Transfer and Friction Factor Characteristics in Turbulent Flow through a Tube Fitted with Screw Tape Ganesh R. Ghodake P.G. Student Department of Mechanical Engineering JSPM’s Imperial College of Engineering & research, Wagholi Pune (M.S.) India Dr. Rahulkumar S. Hingole Professor Department of Mechanical Engineering JSPM’s Bhivrabai Sawant Institute of Technology and Research Wagholi Pune 412207
Dr. Kishore P. Kolhe Professor Department of Mechanical Engineering JSPM’s Imperial College of Engineering & research, Wagholi Pune (M.S.) India
Abstract The methods of augmentation heat transfer are widely utilized in many applications in the heating process to enable reduction in weight and size or increase the efficiency of heat exchangers. These methods are classified as passive, active and combination of (active & passive) these two techniques. For implementing active technique it is required external power such as electric or acoustic fields and surface vibration, whereas while adopting the passive techniques required special surface geometries, fluid additives, swirl/vortex flow devices, that is various types of tape inserts. The passive techniques are better the active techniques because the manufacturing process swirl formation inserts is simple and can be easily implemented in an existing heat exchanger. Moreover the passive techniques can play an important role in the intensification of heat transfer. According to working conditions a proper configuration of the insert is being selected .A Copper tube of 21 mm internal diameter and 25 mm outer diameter and 1000 mm test length was used. The heat transfer parameters was carried out by conducting an experimental study in tube with twisted tape and Screw tape with different diameters for Reynolds number range of 12,000 to 25000. The heat transfer coefficient, friction factor, Nusselt number, Thermal Performance Factor and enhancement efficiency of the twisted tape and Screw tape with different diameters have been obtained and compared with the plain tube. The comparisons showed that, compared with the twisted tape, the Screw tape with different diameters has further improved convective heat transfer performance by about 15 to 20 % and whereas lowered flow friction. The Screw tape with different diameters shows about 25% greater thermal performance than twisted tape at a cost of very low friction factor values. Keywords- Heat transfer; twisted tape; Screw Tape with three different diameters; Nusselt number, friction factor, Thermal performance Parameter
I. INTRODUCTION Many researchers were investigated for augmentation of heat transfer rates inside circular tubes using wide range of inserts when turbulent flow is considered. The inserts studied included coil wire inserts, brush inserts, mesh inserts, strip inserts, twisted tape inserts right-left helical screw inserts etc. Heat exchangers have plays vital role in many industrial applications for example, coolant filtration systems, chilling oil units, heat recovery processes, food and dairy processes air conditioning and refrigeration systems etc. The design of heat exchanger needs exact analysis of heat transfer rate and pressure drop, for better performance and economic aspects of the equipment. Garc et al. [1] investigated and flow patterns in the tube with wire coil inserts in case of the laminar–transition–turbulent flow heat transfer enhancement. Hsieh et al. [2] experimentally studied the flow characteristics in a horizontal circular tube with strip-type inserts for the turbulent heat transfer domain. Bhuiya et al. [3] studied with inserts like twisted wire brush fitted in a circular tube the heat transfer performance and friction factor characteristics were investigated experimentally. It was achieved by 5 mm diameter of two twisted iron core-rods were winded by a 1 mm diameter of the copper wire over a. The densities are 100, 150, 200, and 250 wires per centimeter used for experimentation. For Reynolds number ranging from 7,200 to 50,200, and examining heat transfer and friction factor data in tubes. It is found that due to twisted wire brush inserts the heat transfer performance and friction factor characteristics in a tube for turbulent flow are affected by means of generation swirl. The twisted wire brush inserts have great significance on intensification of heat transfer rate with the penalty in increase in friction factor, which leads high power consumption. At the comparable Reynolds number the friction factor obtained for the tube with twisted wire brush inserts varied from 1.35 to 2.0 times than that of the plain tube values. With the increase of twisted wire densities it was found that the Nusselt number, thermal performance factor, and friction factor increased. At
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